Ambient

Light

Sensor

Ambient Light

Compensation Curve

PWM

Input Pin

Brightness

Value

SMBus/I

2

C

PWM

Compensation Curve

X

Temperature

Limitation

threshold

Phase Shift

PWM

Internal

Temperature

Sensor

Constant Current

LED Drivers

SMBus/I

2

C

Current

Value

Duty Cycle

Measurement

Ambient

Light

Interface

BOOST

LED

DRIVER

LOGIC

EEPROM

I

2

C/

SMBUS

INTERFACE

LDO

OSC

TSD

PWM

DETECTOR

LP8543

SW

FB

GND

GND_SW

GND_LED

EN

PWM

ADR

SCLK

SDA

OUT1

OUT2

OUT3

OUT4

OUT5

OUT6

ALS

INTERFACE

ALSO

FAULT

IF_SEL

ALSI

OUT7

TEMP

SENSOR

MCU

ALS

5.5 ± 22V

LP8543

www.ti.com

SNVS604D – AUGUST 2009 – REVISED MARCH 2013

Block Diagram

LED Driver Control

Basic Operation

Principle of the LED driver control is shown in the following figure:

Figure 11. Principle of the LED Control Methods

LP8543 is designed to be flexible to support backlighting needs for the main display as well as lighting needs of

a sub display (also for e.g. keyboard lighting or status LED) when required. In addition, a variety of PWM options

are supported to drive the backlight LED strings. Various configurations that are supported using a set of

programmable internal registers and EEPROM are described below. Both the register map and the EEPROM

memory map are listed at the end of this datasheet.

Copyright © 2009–2013, Texas Instruments Incorporated

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